Andrew, Sabena being the known perfectionists, I don’t think they would stick the flag the wrong way! It wlould be very disgraceful for a FLAG carrier!
I mostly fly flag carriers for shorter flights because these are affordable. I fly where we can afford to fly to, it also depends on the distance. 330 euros return ticket from brussels to jfk with klm is a very reasonable price. however 275 euros from brussels to moscow is rather expensive.
actually anyone can make such picture, but the timing is propably a bit hard! plus, you’ll need a high shutterspeed, or follow the aircraft with the lense!
It always surpises me how they fit the aircraft exactly in the picture. I always make pictures 2304 pixels wide and then cut out what I want. This is good for me because my camera only has 105 mm of zoom.